The present invention relates to platform or header suspensions for crop harvesting implements and more specifically relates to platform suspensions using hydraulic float cylinders for carrying a majority of the weight of the platform during crop cutting operations.
Platform or header suspensions are known which utilize one or more hydraulic cylinders coupled in a closed hydraulic system so as to be in parallel with an accumulator. Float is adjusted by adding or removing oil from the system. This latter function in some systems is accomplished electrohydraulically with a rocker switch in the cab of the machine. Systems like this typically display the float system pressure on a gauge in the cab. This reference is used to monitor float pressure or to return to a float pressure setting used previously.
If the system pressure is too low, an excessive amount of platform weight is carried by the platform skid shoes or gauge wheels. This can result in premature wear on the shoes, or mechanical damage to the platform or to components linking the platform to the traction unit. Low pressure can result from internal leakage during storage periods, from intentional discharge, for example, when one platform is exchanged for another, or from unintentional discharge from inadvertent operation of the discharging switch by an operator unfamiliar with the system. Because an operator may become preoccupied with other tasks during mowing operation and not notice the pressure gauge or not know what the desired float pressure should be, a warning system is needed to let the operator know that the system is operating at an unacceptably low pressure.